Fuselage to wing attachment

ABSTRACT

According to one embodiment, an aircraft features a fuselage, a wing member, and two fuselage beam. The fuselage features a first plurality of structural supports, a second plurality of structural supports, a first opening disposed between the first plurality of structural supports, and a second opening disposed between the second plurality of structural supports. The wing member is disposed above the first opening and above the second opening. The wing features a plurality of ribs including a first rib and a second rib. The first fuselage beam couples the first rib of the wing member to the fuselage and has an elongated body portion extending across the first plurality of structural supports. The second fuselage beam couples the second rib of the wing member to the fuselage and features an elongated body portion extending across the second plurality of structural supports.

GOVERNMENT RIGHTS

At least some of the subject matter of this application may have beenmade with government support under W911W6-13-2-0001 awarded by theUnited States Army under the Future Vertical Lift program. Thegovernment may have certain rights in the invention.

TECHNICAL FIELD

This invention relates generally to aircraft fuselages, and moreparticularly, to a fuselage to wing attachment.

BACKGROUND

A rotorcraft may include one or more rotor systems. One example of arotorcraft rotor system is a main rotor system. A main rotor system maygenerate aerodynamic lift to support the weight of the rotorcraft inflight and thrust to counteract aerodynamic drag and move the rotorcraftin forward flight. Another example of a rotorcraft rotor system is atail rotor system. A tail rotor system may generate thrust in the samedirection as the main rotor system's rotation to counter the torqueeffect created by the main rotor system.

SUMMARY

Particular embodiments of the present disclosure may provide one or moretechnical advantages. A technical advantage of one embodiment mayinclude the capability to provide a wing located over a door opening inan aircraft such as a tiltrotor aircraft. A technical advantage of oneembodiment may include the capability to accommodate the various forcestransmitted from the wing to the fuselage of an aircraft such as atiltrotor aircraft.

Certain embodiments of the present disclosure may include some, all, ornone of the above advantages. One or more other technical advantages maybe readily apparent to those skilled in the art from the figures,descriptions, and claims included herein.

BRIEF DESCRIPTION OF THE DRAWINGS

To provide a more complete understanding of the present invention andthe features and advantages thereof, reference is made to the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 shows a tiltrotor aircraft according to one example embodiment;

FIG. 2 shows a stress analysis of the wing and one of the openings ofthe tiltrotor aircraft of FIG. 1 one example configuration;

FIGS. 3-6 show a structural configuration installed on the tiltrotoraircraft of FIG. 1;

FIG. 3 shows a perspective view of the structural configuration with thewing enclosed;

FIG. 4 shows a perspective view of the structural configuration of FIG.3 with the external skin of the wing removed;

FIG. 5 shows a side view of some of the main structural elements of thetiltrotor aircraft of FIG. 1; and

FIG. 6 shows an end view of some of the main structural elements of thetiltrotor aircraft of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a rotorcraft 100 according to one example embodiment.Rotorcraft 100 features rotor systems 110 a and 110 b, blades 120, afuselage 130, a landing gear 140, a wing 150, and an empennage 160.

Rotor system 110 may rotate blades 120. Rotor system 110 may include acontrol system for selectively controlling the pitch of each blade 120in order to selectively control direction, thrust, and lift ofrotorcraft 100. In the example of FIG. 1A, rotorcraft 100 represents atiltrotor aircraft, and rotor systems 110 a and 110 b feature rotatablenacelles. In this example, the position of nacelles 110 a and 110 b, aswell as the pitch of rotor blades 120, can be selectively controlled inorder to selectively control direction, thrust, and lift of tiltrotoraircraft 100.

Fuselage 130 represents the main body of rotorcraft 100 and may becoupled to rotor system 110 (e.g., via wing 150) such that rotor system110 and blades 120 may move fuselage 130 through the air. Landing gear140 supports rotorcraft 100 when rotorcraft 100 is landing and/or whenrotorcraft 100 is at rest on the ground.

Teachings of certain embodiments relating to rotor systems describedherein may apply to rotor system 110 and/or other rotor systems, such asnon-tilting rotor and helicopter rotor systems. It should also beappreciated that teachings from rotorcraft 100 may apply to aircraftother than rotorcraft, such as airplanes and unmanned aircraft, to namea few examples.

In the example of FIG. 1, tiltrotor aircraft 100 may operate in ahelicopter mode by tilting the nacelles upright and in an airplane modeby tilting the nacelles forward. Tiltrotor aircraft 100 may generategreater forward speed in airplane mode than in helicopter mode because,in airplane mode, blades 120 are oriented to generate greater thrustpropelling the aircraft forward (somewhat analogous to a propeller).

Rotorcraft 100 also features at least one empennage 160. Empennage 160represents a flight control surface coupled to the tail portion offuselage 130. In the example of FIG. 1, rotorcraft 100 features twoempennage sections 160. In this example embodiment, the combination ofthe two empennage sections 160 may represent a v-tail configuration.

In operation, rotor systems 110 a and 110 b may generate vibrations,pitching moments, and other forces that may be transferred from thenacelles to fuselage 130 via wing 150. These forces and vibrations maybe more extreme than the forces imparted by a wing on a typicalfixed-wing aircraft due to the activity of rotor systems 110 a and 110b. Accordingly, the structure of rotorcraft 100 should be configured toaccommodate these forces.

In a typical aircraft, a wing might be attached to the fuselage via acombination of pins and links. These links may be capable oftransmitting load from the wing into the fuselage while permitting thewing to bend and flex independently of the fuselage.

In the example of FIG. 1, however, fuselage 130 features two largeopenings 132 a and 132 b underneath wing 150. These openings 132 a and132 b are both large enough to allow ingress and egress of humanpassengers, such as military personnel. Each opening has a correspondingdoor 134 a and 134 b that is configured to open and close thecorresponding openings 132 a and 132 b.

The presence of openings 132 a and 132 b may present technicalchallenges to achieve the necessary pitch stiffness requirements. Forexample, FIG. 2 shows a stress analysis of wing 150 over opening 132 ain one example configuration. In the example of FIG. 2, moment forcesexerted on wing 150 cause wing 150 to exert significant downward forceson the aft portion of opening 132 a. As seen in this example, thesemoment forces cause deformation of the top of opening 132 a becauseopening 132 a does not contain the necessary structure to carry theseforces.

Because the presence of openings 132 a and 132 b present such technicalchallenges, replacing openings 132 a and 132 b with structure couldovercome these technical challenges. However, in some circumstances, thepresence of openings 132 a and 132 b under wing 150 are required inorder to perform certain missions. For example, placing openings 132 aand 132 b under wing 150 may improve troop ingress and egress ascompared to a rear-hatch door. In addition, placing openings 132 a and132 b under wing 150 may allow wing 150 to also function as a windscreenby blocking the airflow (e.g., downwash) generated by rotor systems 110a and 110 b. Placing openings 132 a and 132 b under wing may alsoimprove fast rope and other activities during hovering.

Accordingly, teachings of certain embodiments recognize the capabilityto provide openings under the wing of an aircraft such as rotorcraft 100even though doing so may raise technical challenges. Teachings ofcertain embodiments also recognize the capability to provide openingsunder the wing of an aircraft such as rotorcraft 100 even though doingso may result in a heavier design, a more complicated assembly process,or other penalties because of the steps that may be taken to overcomethe technical challenges.

FIGS. 3-6 show a structural configuration 200 that may overcome thetechnical challenges incurred when placing openings 132 a and 132 bunder wing 150 according to one example embodiment. FIG. 3 shows aperspective view of structural configuration 200 with wing 150 enclosed,FIG. 4 shows a perspective view of structural configuration 200 with theexternal skin of wing 150 removed, FIG. 5 shows a side view of some ofthe main structural elements of rotorcraft 100, and FIG. 6 shows an endview of some of the main structural elements of rotorcraft 100.

In the example of FIGS. 3-6, structural configuration 200 featuresfuselage beams 210 a and 210 b, forward attach fittings 220 a and 220 b,aft attach fittings 230 a and 230 b, and lateral links 240 a and 240 b.As also seen in the example of FIG. 4, wing 150 features multiple ribs152, including ribs 152 a and 152 b.

In these examples, each fuselage beam couples wing 150 to fuselage 130.For example, fuselage beam 210 a couples rib 152 a of wing 150 tofuselage 130, and fuselage beam 210 b couples rib 152 b of wing 150 tofuselage 130.

In these examples, the fuselage beams are coplanar with their respectivewing ribs. In fact, the fuselage beams form a continuous structuralelement with their respective wing ribs such that each beam/ribcombination operates substantially like a single member. In the exampleof FIGS. 3 and 4, each rib 152 a and 152 b is joined to itscorresponding fuselage beam 210 a and 210 b via a single, uninterruptedjoint. This single, uninterrupted joint eliminates any major openings orgaps that might be present on pinned wing attachments and allows forforces to be transmitted between the rib and the beam as if they were asingle structural element.

Teachings of certain embodiments recognize that attaching the wing ribsof wing 150 to fuselage beams 210 a and 210 b in a coplanar, continuousmanner, such as shown in FIGS. 3-4, may allow structural configuration200 to accommodate the various forces imparted by wing 150 even thoughopenings 132 a and 132 b are located under wing 150. As will beexplained in greater detail below, both fuselage beams include anelongated body portion that extends across their corresponding openingsin fuselage 130 and distributes loads to both sides of the correspondingopenings, as seen in the example of FIG. 2.

In the examples of FIGS. 3 and 4, wing 150 has an airfoilcross-sectional shape. As such, ribs 152 a and 152 b of wing 150 featurean outer contour that corresponds to this airfoil shape. Because, asexplained above, ribs 152 a and 152 b may be coupled to fuselage beams210 a and 210 b along a single, uninterrupted joint such that eachrib/beam combination forms a coplanar, continuous, structural element,fuselage beams 210 a and 210 b also feature a top surface thatcorresponds to the outer contour of the wing ribs. In this example, thetop surface of fuselage beams 210 a and 210 b can receive the wing ribs152 a and 152 b without creating any major openings or gaps betweenfuselage beams 210 a and 210 b and wing ribs 152 a and 152 b.

In the example of FIGS. 3 and 4, however, the top surfaces of fuselagebeams 210 a and 210 b do not follow the entire contours of wing ribs 152a and 152 b. Instead, only the bottom portion of wing ribs 152 a and 152b are received by fuselage beams 210 a and 210 b, and the top portion ofwing ribs 152 a and 152 b follow the aerodynamic profile of the top ofwing 150. This arrangement creates two gaps between the top and bottomportions of wing ribs 152 a and 152 b: one gap forward of wing ribs 152a and 152 b, and one gap aft of wing ribs 152 a and 152 b.

These gaps are filled by forward attach fittings 220 a and 220 b and aftattach fittings 230 a and 230 b. In these examples, forward attachfittings 220 a and 220 b and aft attach fittings 230 a and 230 b arecoplanar with their respective fuselage beams and wing ribs. In fact,the fuselage beams, wing ribs, and attach fittings form continuousstructural elements such that each beam/rib/fitting combination operatessubstantially like a single member.

In these examples, fuselage beam 210 a, wing rib 152 a, forward attachfitting 220 a, and aft attach fitting 230 a form a single, structuralmember that resembles an I-beam with a variable web height. For example,fuselage beam 210 a provides the lower flange and a lower portion of theweb of the I-beam, and fuselage beam 210 a, wing rib 152 a, forwardattach fitting 220 a and aft attach fitting 230 a each provide a portionof the upper flange and an upper portion of the web of the I-beam. Thisconfiguration allows the combined structural element to resist shear andbending forces, which makes the configuration particularly well suitedto respond to loads imparted by wing 150 during operation of rotorcraft100.

As stated above, both fuselage beams include an elongated body portionthat extends across their corresponding openings in fuselage 130 anddistributes loads to both sides of the corresponding openings instead offocusing the forces on the top of the openings, as is the case in FIG.2. More specifically, each opening 132 a and 132 b is surrounded by apair of structural supports, and the elongated body portions of fuselagebeams 210 a and 210 b span these supports. Because ribs 152 a and 152 bform continuous structural elements with corresponding fuselage beams210 a and 210 b, the elongated body portions of fuselage beams 210 a and210 b allow the forces received from wing 150 to be distributed to thestructural supports surrounding openings 132 a and 132 b, which arebetter equipped to accommodate those forces instead of the open spacewithin openings 132 a and 132 b.

In fact, as seen in the example of FIGS. 5 and 6, fuselage 130 includesseven structural supports 132 a-132 g, although embodiments of fuselage130 may include more or fewer supports. In this example embodiment, theelongated portion of each fuselage beam extends such that the forces aredistributed to each of the seven structural supports 132 a-132 g.Looking from the end view of FIG. 6, each fuselage beam 210 a and 210 bis aligned over the top of the structural supports 132 a-132 g such thatthe forces are directly transferred to the structural supports 132 a-132g.

Modifications, additions, or omissions may be made to the systems andapparatuses described herein without departing from the scope of theinvention. The components of the systems and apparatuses may beintegrated or separated. Moreover, the operations of the systems andapparatuses may be performed by more, fewer, or other components. Themethods may include more, fewer, or other steps. Additionally, steps maybe performed in any suitable order.

Although several embodiments have been illustrated and described indetail, it will be recognized that substitutions and alterations arepossible without departing from the spirit and scope of the presentinvention, as defined by the appended claims.

To aid the Patent Office, and any readers of any patent issued on thisapplication in interpreting the claims appended hereto, applicants wishto note that they do not intend any of the appended claims to invokeparagraph 6 of 35 U.S.C. § 112 as it exists on the date of filing hereofunless the words “means for” or “step for” are explicitly used in theparticular claim.

1.-18. (canceled)
 19. An aircraft, comprising: a fuselage comprising afirst plurality of structural supports along a first side of theaircraft, a second plurality of structural supports along a second sideof the aircraft, a first door opening between two structural supports ofthe first plurality of structural supports, and a second door openingbetween two structural supports of the second plurality of structuralsupports; a wing comprising a first rib and a second rib, wherein thefirst door opening and the second door opening are under the wing; afirst fuselage beam comprising an elongated body portion aligned overthe first plurality of structural supports; and a second fuselage beamcomprising an elongated body portion aligned over the second pluralityof structural supports, wherein the first fuselage beam is coupled tothe first rib of the wing and the second fuselage beam is coupled to thesecond rib of the wing.
 20. The aircraft of claim 19, furthercomprising: a rotor system coupled to the wing, wherein the rotor systemis, at least in part, tiltable between a helicopter mode position and anairplane mode position.
 21. The aircraft of claim 19, wherein the firstrib and the first fuselage beam are coplanar, and the second rib and thesecond fuselage beam are coplanar.
 22. The aircraft of claim 19, whereinthe first rib and the first fuselage beam form a continuous structuralelement and the first rib is joined to the first fuselage beam along asingle, uninterrupted joint.
 23. The aircraft of claim 22, wherein thesecond rib and the second fuselage beam form a continuous structuralelement and the second rib is joined to the second fuselage beam along asingle, uninterrupted joint.
 24. The aircraft of claim 19, wherein thefirst rib comprises an outer contour that corresponds to across-sectional shape of the wing, the second rib comprises an outercontour that corresponds to the cross-sectional shape of the wing, thefirst fuselage beam comprises a top surface that corresponds to theouter contour of the first rib, and the second fuselage beam comprises atop surface that corresponds to the outer contour of the second rib. 25.The aircraft of claim 24, wherein the first rib is coupled to the firstfuselage beam where the top surface of the first fuselage beam receivesthe outer contour of the first rib, and the second rib is coupled to thesecond fuselage beam where the top surface of the second fuselage beamreceives the outer contour of the second rib.
 26. The aircraft of claim19, further comprising a first door to open and close at the first dooropening and a second door to open and close at the second door opening.27. The aircraft of claim 19, wherein the first door opening and thesecond door opening are both so dimensioned as to allow ingress andegress of a human passenger.
 28. The aircraft of claim 19, furthercomprising a first forward attach fitting coupled to the first fuselagebeam and the first rib forward of the wing and a first aft attachfitting coupled to the first fuselage beam and the first rib aft of thewing.
 29. The aircraft of claim 28, wherein the first rib, the firstfuselage beam, the first forward attach fitting, and the first aftattach fitting are coplanar and form a continuous structural element.30. The aircraft of claim 29, wherein the first fuselage beam forms anI-beam in combination with the first rib, the first forward attachfitting, and the first aft attach fitting, wherein the first fuselagebeam forms a lower portion of the I-beam and the first rib, the firstforward attach fitting, and the first aft attach fitting, form an upperportion of the I-beam.
 31. The aircraft of claim 28, further comprisinga second forward attach fitting coupled to the second fuselage beam andthe second rib forward of the wing and a second aft attach fittingcoupled to the second fuselage beam and the second rib aft of the wing.32. The aircraft of claim 31, wherein the second rib, the secondfuselage beam, the second forward attach fitting, and the second aftattach fitting are coplanar and form a continuous structural element.33. The aircraft of claim 32, wherein the second fuselage beam forms an!-beam in combination with the second rib, the second forward attachfitting, and the second aft attach fitting, wherein the second fuselagebeam forms a lower portion of the I-beam and the second rib, the secondforward attach fitting, and the second aft attach fitting, form an upperportion of the I-beam.
 34. The aircraft of claim 33, further comprisingone or more first lateral links coupled between a roof of the fuselageand at least one of the first rib, the first fuselage beam, the firstforward attach fitting, and the first aft attach fitting.
 35. Theaircraft of claim 34, further comprising one or more second laterallinks coupled between the roof of the fuselage and at least one of thesecond rib, the second fuselage beam, the second forward attach fitting,and the first aft attach fitting.
 36. The aircraft of claim 19, whereinthe elongated body portion of the first fuselage beam distributes forcesreceived from the wing to the two structural supports of the firstplurality of structural supports that the first door opening is between.37. The aircraft of claim 19, wherein the elongated body portion of thesecond fuselage beam distributes forces received from the wing to thetwo structural supports of the second plurality of structural supportsthat the second door opening is between.
 38. The aircraft of claim 19,wherein the elongated body portion of the first fuselage beamdistributes forces received from the wing to the first plurality ofstructural supports and the elongated body portion of the secondfuselage beam distributes forces received from the wing to the secondplurality of structural supports.